1. Field of the Invention
The present invention relates generally to circuit breakers and more particularly to improvements in the control and monitoring of remotely controlled circuit breakers.
2. Descriptions of the Related Art
Remotely controlled circuit breakers are commonly used for temporary interruption of electrical power to electrical devices during peak use hours and for programmable control. of lighting and other devices in commercial applications. By selectively opening and closing from remote locations, such circuit breakers can provide energy savings and convenience of operations over manually operated circuit breakers. For these reasons, remotely controlled circuit breakers are increasingly being used in various industries and office buildings alike.
Remotely controlled circuit breaker systems typically include a circuit breaker load-center having circuit breakers wired to a remotely located control unit, such as a computer, for monitoring and/or controlling the individual circuit breakers. U.S. Pat. No. 4,920,476 issued to Brodsky et al. on Apr. 24, 1990, shows a circuit breaker system wherein the wiring is accomplished by using a patch-board within the load-center. Other systems use hard-wiring between each circuit breaker input/output and a terminal in the remotely located computer. Such systems are not flexible, in that each time the circuit breaker control requirements change, the wiring and many system components must be reconfigured or replaced, which can be expensive and burdensome.
The parent co-pending patent application U.S. Ser. No. 07/723,474, filed on Jun. 28, 1991 and assigned to the assignee of this application, provides an electrical power distribution system which solves the above-noted problems. It includes multiple circuit breakers, each of which is operable by remote control in at least an open and a closed position. A circuit breaker control circuit having a termination circuit interprets circuit breaker control signals from an external switch device. A circuit breaker driver board controls and monitors the circuit breaker input means. Data paths are provided for receiving programming data from an external device. A switch input data path coupled to the termination circuit carries circuit breakers switching instructions from the termination circuit. The control circuit responds to manual input instructions, programming data and circuit breaker switch instructions according to a prioritization scheme. The parent patent application U.S. Ser. No. 07/723,474, filed on Jun. 28, 1991, is incorporated herein by reference.
The above described circuit breaker system is enclosed in a single panel, which has a limited capability to accept inputs from various external switches or devices, which in many applications significantly reduces the capability of such circuit breaker systems. Additionally, no means are provided to remotely display the status of individual circuit breakers or to operate other devices as a function of the status of the individual circuit breakers.
The present invention provides an electrical distribution system having the above described circuit breaker unit or the load panel and an expander unit. The expander unit enables the circuit breaker unit to utilize a large number of inputs from various external switches and/or devices. The expander unit also displays the status of the individual circuit breakers at a remote location and is adapted to drive or operate other devices as a function of the status of the individual circuit breakers.